Letter A

The Definition of AD

Arsenal Exchange - Firearms Classifieds - Industry Directory


Abbreviation for Accidental Discharge

19 Other Firearms Definitions You Need To Know

Ghost-Ring Sight

A type of aperture rear sight with a large opening and a thin rim that seems to fade out when the shooter looks through it. Sometimes installed on rifles and shotguns intended for home defense or police use.

Cartridge Overall Length

This is the maximum overall length the cartridge can be (and is expected to be) in order to function properly in magazines and the mag well of a bolt action rifle.


Slang for a gun or the action of carrying a gun concealed, e.g "The Bersa Thunder .380 is a fantastic gun for carrying" or "Do you carry?".

Heavy Trigger

A trigger that requires a lot of pressure to pull it past the break point. Rifles tend to have considerably lighter triggers than handguns, and even a heavy rifle trigger is often lighter than a light handgun trigger.


Originally used to describe the spherical projectile used in black powder firearms, now also used to refer to a fully jacketed bullet of cylindrical profile capped with a round nose

Bolt Action

A type of firearm action in which the guns's bolt is operated manually by the opening and closing of the breech (barrel) with a small handle. As the handle is operated, the bolt is unlocked, the breech is opened, the spent shell casing is withdrawn and ejected, the firing pin is cocked, and finally a new round/shell (if available) is placed into the breech and the bolt closed.


That part of the stock on a rifle or shotgun into which the barrel fits.

English Grip

A straight-wrist grip, typical on English shotguns, built for graceful aesthetics, light weight and fast handling.

Failure To Fire

Any malfunction that results in no shot fired when the trigger is pulled. Commonly caused by a failure to feed, bad ammunition or a broken firing pin.


The device that aids the eye in aiming the barrel of a firearm in the proper direction to hit a target.They can be a mechanical, optical, or electronic device. Iron sights or sometimes as open sights, consist of specially-shaped pieces of metal placed at each end of the barrel. The sight closest to the muzzle end of the gun is called the front sight, while the one farthest from the muzzle (and nearest to the shooter) is called the rear sight.


A rifle with a relatively short barrel.


A tiny circular recess at the base of a cartridge case surrounding the primer pocket. Recoil from fired cartridges invariably impress a discernable ring on the breech or bolt face of a firearm, providing some evidence of the amount of use it has seen.

Smooth Bore

A barrel without rifling. Smooth bore barrels are commonly used in shotguns and in large bore artillery that fire fin stabilized projectiles.


The spotter is a helper who gives the shooter guidance on how to hit a particular target. In some cases the spotter may just report the location of the bullet impact. In other cases they may judge the speed and direction of the wind, determine the range, and give the shooter the settings to be used on the sights.


A gun with more than one barrel, the most common being the double-barreled shotgun.


A set of holes in a target left by a succession of bullets fired from the same rifle or handgun, using the same ammunition and sight setting. Fired (within the limits of one's marksmanship ability) to determine the inherent accuracy of the rifle/ammunition combination, and to aid in the proper adjustment of the sights.


A box of ammunition roughly equal in size and weight to a brick. Most often used to describe a 500-round container of .22 Long Rifle ammunition.

Dust Cover

A small hinged or sliding door covering the ejection port of a firearm to prevent detritus from clogging the works.


A unit of weight widely used to express the weight of bullets and of powder charges. Equal to 1/7000 pound.